Okta App Centre Integration with Azure AD B2C - azure-ad-b2c

I am trying to integrate the Okta App Centre with Azure AD B2C. This would involve a SPA App as well as a Mobile App that would be hopefully be able to use the Context from the Okta App Centre to directly sign the User in and follow the User Journey as if they had clicked a sign in button. I am using Custom Policies.
I have set up an OpenIdConnect App Integration on the Okta side and it is working to sign in a user into B2C. On the Okta App sign in uri, I am using a domain_hint to use the Okta sign in path "invisibly" as well as passing a redirect_uri so that the sign in redirects to the SPA App.
This works, but I'm just wondering if overall this is the best way to accomplish this. I saw in another Stack Overflow mention of using an SP-Initiated flow using SAML instead. One issue I noticed with this approach potentially is the Sign In link for the App has a limit of 255 characters on the Okta side, which is not long enough to build the sign in URL I would need for the SPA. Would the SP-Initiated be a better experience though? I'm just trying to figure out how I would include the redirect_uri as well as the scopes into the initial SAML sign in request, both of which make for a long initial sign in URL (I wonder if I am missing something).

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What is the flow of Azure AD based authentication in a project having SPA and web api?

I have a front end SPA (single page application) and back end api.
Each event in the SPA (like button click) invokes the respective api endpoint, and displays the result in the SPA.
I want to implement Azure AD based authentication so that only my Azure Tenant users are able to use the SPA/api.
Is the following flow correct approach to implementing such a feature:
User opens the SPA
User clicks on login button which opens Microsoft login popup
User enters Microsoft credentials in the popup, and if credentials are correct then user gets the JWT token
For every subsequent api request, the JWT token is placed in the bearer header
The endpoint validates the JWT token using Azure public key and rejects the request if token is missing or validation fails.
Is this flow correct and what is such a flow called?
There are several implementation steps that needs to be performed before you will have the flow that you have described:
User flow needs to be configured (Azure AD) - e.g. selfsignup allowed?
Backend and frontend applications needs to be registered (Azure AD)
Permissions and scopes needs to be added (Azure AD)
Backend API needs to be configured (e.g. API management) in order to validate the JWT token
I highly recommend to configure one of the Azure sample implementations end2end to get and idea of all the needed tasks: https://learn.microsoft.com/en-us/azure/active-directory-b2c/configure-authentication-sample-spa-app
The steps you outlined are correct.
An OAuth 2.0 "flow" outlines the steps to acquire a token from an Identity Provider (IdP). Since you are using a SPA, there are some restrictions on which flows you can use. A SPA can't act as a "Confidential Client" which is required for some flows. (Basically - the Client Secret required for the other flows would be visible in the browser network trace, so it's not "confidential".) The "Implicit Flow" used to be recommended for SPAs but it's less secure, so now the "Authorization code flow (with PKCE)" is recommended. Steps 2 & 3 in the question above are when you are executing the flow to acquire a token.
The authentication flow doesn't really address how you save and send the token to the API (#4 in the question), but the Microsoft Authentication Library (MSAL) helps with that - More information here - https://learn.microsoft.com/en-us/azure/active-directory/develop/scenario-spa-overview
In Azure AD, you'll want 2 App Registrations - one for your SPA and one for your API. The API App Registration will need to "Expose an API" which really means to define a scope. Your SPA App Registration will need to Add an "API Permission" to the scope you defined from your API App Registration. (It will show up in My APIs.) This relationship is how #5 in the question is enforced.
Many of the steps for setting up authentication in Azure AD and Azure B2C are similar but Azure AD is designed for authenticating users that are part of your organization. Azure B2C allows you to build a set of users that aren't members of a particular Azure AD organization.

User-Consent screen not showing when using Postman and .Net 6 Web Api

So I am writing a .NET 6 Core Web Api using Azure AD as authentication for the API.
Now when using Graph API as example, you need to setup Graph API scopes in the App Registration. Lets use a delegated "user.read" permission for this example.
I use Postman to receive the access token for the application by authenticating as an user against Azure AD for the API. I would expect to receive a consent-screen so I can consent to the usage of "user.read". This does not happen though.. I get logged in and receive a valid access token. In the Backend though, it will throw an error because the user / admin did not consent to the application.
How do I get around this? Why don't I get asked to consent the permissions set up in the app registration? Neither in Postman, nor in a Swagger oAuth Flow..
My current workaround for this is to use a React application and sign in over the frontend application. Using the frontend application, I get asked to consent to the permissions. After consenting, I can use postman without getting the "user didn't consent" - error.
Any ideas? What did I miss?
Let's focus on the user-consent page first. When we created an azure ad app then add api permission for it, then use this azure ad app to make your .net 6 app/react app integrate azure ad to use azure authentication, and we go to the microsoft sign in page and successfully sign in, we will see a dialog which indicating that this app require you to consent a list of permissions. The permissions are correspond to the api permissions you set for the aad app. After consent once, then it won't ask you to consent again when sign in next time.
This consent only happened when users are signed in. Let's go back to the flows used to generate access token in Azure AD. Since you used delegate permission, then you may used the recommend Auth code flow(Another flow called ROPC flow can also generate delegate access token but not recommended). When we used auth code flow, we need to sign in first, the login url should look like this:
https://login.microsoftonline.com/tenant.onmicrosoft.com/oauth2/v2.0/authorize?client_id=azure_ad_app_id
&response_type=code
&redirect_uri=http://localhost/myapp/
&response_mode=query
&scope=user.read
&state=12345
We need to use it to get the auth code, then we can use the code to generate access token, per my test, I created a new azure ad app and when I directly hit this url in the browser and sign in, it still required me to give the consent. So I'm afraid the reason why you didn't see the dialog when test in post man is that you've consent it when test in react app, or you don't use auth code flow.

python3-saml and Azure AD - missing a point

Good afternoon experts,
I have a Django web application (it is not internet-facing) and so far I used the django.contrib.auth.backends.ModelBackend to authenticate the users.
However I want to integrate this webapp to an existing SSO solution (like Azure AD) so I thought python3-saml would be a good library to be used (more specifically I use python3-saml-django but it is just a wrapper around python3-saml).
Probably I am missing some fundamental point as I don't really understand how this should work.
When I used ModelBackend then I had a login form where the user could type their username+password which was checked against Django database and the authentication was completed. Should the same work with SSO too? i.e. the login form appears, the user will type their credentials but they will be checked in Azure AD instead of Django auth tables? Or the custom login form of that specific auth solution (in this case Azure AD -> Microsoft login form) should be displayed...?
The LOGIN_URL setting is configured in my Django app so if no user is logged in then automatically my login form appears.
Also I set the AUTHENTICATION_BACKENDS setting and it points only to django_saml.backends.SamlUserBAckend.
I configured AZure AD (registered the app and added a user, I tested it in Azure AD console) hopefully correctly. I also populated python3-saml's settings.json with login/logout URL, etc.
Whenever I try to log in with the Azure AD user I got an auth error (the user and password did).
I am just wondering if somebody could shed some light please how this should work? Can I debug the SAML requests / responses?
auth is token based in azure ad and it will redirect the user to the microsoft login. You will receive an auth token which then you can use to for authorization and providing secure pages.
First register your app in azure portal in azure active directory and also create a user flow.
Then download MSAL for python (using pip) which is used for auth using azure ad for python.
The basic architecture is that when the user tries to login the Microsoft login page will be shown, after signing in your app will receive a token which then you should use to show the logged in pages.
References:
quickstart for auth in python
userflow
MSAL Library

How can I authenticate a windows app with AAD B2C without the B2C login pages?

I have an mvc app that provides both a website and a webapi. I'm happily authenticating users of the website. Now I need to allow a windows app to call the web api methods directly. I don't want the windows app to redirect to a login page. I need the windows app to hold either a secret key or a username/password. That way it can authenticate itself automatically.
I'm concerned that it seems b2c cannot handle client credential flow - which I think I want. Is there a way to silently provide the username and password to B2C?
Azure AD B2C does not implement client credentials or ROPC flows of OAuth2. But ROPC is on Azure AD B2C roadmap.
In your case, if you have multiple users using the Windows Application, then you need ROPC because the token retrieved using that mechanism has user context (achieved via user authentication).
Using client_credentials flow means that your Windows Application needs to keep the secret and will authenticate as application only, without any user context. This is ok for daemon and background processes running in a protected environment, but not for apps that you expect to be used by users.
At this point, your best option will be to redirect to Azure AD B2C login pages. Although it is not the same as native experience, the advantages here are that if as you add more options (e.g. MFA, string and language customization, new login options in the future), your client application will not need to be changed, and all your UIs will get those features.

Single Sign on - Multiple application azure AD B2C

I am trying to have two applications(app1 and app2) in Azure
AD B2C, which is configured for Web api and another application that is configured for mobile app.
I need my mobile app to talk to app1, get the access token, using the app1's application-id and scope. Then use the access token got from app1 to communicate with app2. I enabled SSO in tenant level in the policies but it still says "Authorization denied" for the access token provided.
How can I reuse the access token got from one application to be used in another application.
We have been trying to get through this limitation (or function as designed for security) of B2C AD from weeks.
However, Microsoft does not support it.
We did not want to display MS login page to mobile user on mobile login screen (UX gets compromised). But MS says there is no way possible to avoid it. See response from MS on support ticket.
For more information: Azure AD B2C: Requesting access tokens
You will also benefit reading authentication scenarios supported. We are after something similar to this what they call "Daemon or Server Application to Web API".
In this diagram, Server Application = to mobile application in our case. However you will notice that in this scenario it is assumed that the user is already authenticated (via interactive flow).
We tried to act smart, thinking we can write a Auth web API which mobile will hit to obtain token and then pass this token to our business logic API (secured by B2C AD). We obtained access and refresh token somehow, however the test web app (mobile app) when pass this access token to our business logic API, it fails to validate the token. B2C AD comes fighting for it. Our analysis is not yet complete.
However, I am certain what we are trying to accomplish is not supported in B2C AD.
Hope this helps (I would actually advise you to look for other solution). I will be happy if someone can suggest a way to solve this obvious business problem.

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